Scour Protection System

ABSTRACT

A scour protection system comprising one or more bags placed in an underwater location to prevent scour caused by the flow of water, wherein the bags can be filled with matter in situ to form interconnecting blocks, and the visible upper surfaces of the bags resemble rocks or other features.

CROSS-REFERENCES TO RELATED APPLICATIONS

This is the National Phase of PCT Application No. PCT/GB2005/003787having an International Filing Date of 3 Oct. 2005 which claims priorityto British Application No. 0422345.9 filed 8 Oct. 2004.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

Not Applicable

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

Not Applicable

BACKGROUND OF THE INVENTION

The invention to which this application relates is a system forprotecting structures exposed to water from the scouring action of thewater.

Scour is caused by the wearing action of moving water, for example alongthe bed and banks of rivers, and can have serious consequences tostructures exposed thereto such as the supports of bridges due toundermining of the structure's foundations. This can result in thecatastrophic collapse of many structures, leading to potential loss oflife and significant rebuild costs. However, structures can be protectedagainst these effects, and there are several forms of protectioncurrently in use around the world in both fluvial and marine situations.

One such method of scour protection is the use of fabric formworkmattresses (also known as filter-point or constant thicknessmattresses). These mattresses have been used within the constructionindustry for approximately 40 years for protecting river banks, riverbeds, and sea beds from scour and erosion, particularly aroundstructures. Fabric formwork mattresses essentially form a hard layer ofprotection which is designed to resist the effects of scour and, assuch, protect structures from being undermined and/or river banks fromlateral erosion. They consist of a sandwich of high strength, generallyporous, typically woven, synthetic fabric, into which micro-concrete,grout or aggregate concrete is pumped. Mattresses placed below water arelaid and filled in-situ using a diver. Typically, they form extensivemats, similar in shape to bedding mattresses, ranging in thicknessbetween 100 and 350 mm. Once the concrete has set, the result is a solidlayer of protection that can be very effective and resistant to scour.Fabric formwork bags are also available for underpinning works or toprovide support and/or protection to structures, such as pipelines.These bags are amorphous in shape and resemble sand-filled bags, and assuch do not fit together particularly well.

Articulated mattresses are also available and are similar in mostrespects to filter-point mattresses but allow settlement due to flexibleseams. Again, these are generally amorphous in shape, which isdisadvantageous as hereinbefore described. These bags are smoothtextured and when formed are white/light grey in color, which ischaracteristically unnatural in appearance.

There also exists preformed concrete blocks which can be articulated orinterlocking concrete blocks, but these do not enable the placement ofwet concrete below water. The advantage of fabric formwork protection isthat it enables the placement of concrete or gout below water withoutsignificant risk of environmental pollution that would otherwise occurif concrete were allowed to freely enter the river or marineenvironment. The use of concrete can be very effective protectionagainst scour but, in most instances, concrete cannot be placed withoutcomplete dewatering (drainage) of the area to be protected, to protectagainst fouling and environmental pollution from the concrete otherwise,and to provide the necessary formwork. The ability to place concretewithout the need for dewatering has significant advantages over manyother forms of scour protection and can lead to significant cost savingsfor any scour protection scheme. In addition to forming an effectivemeans of protecting a structure, river bank or indeed any interfacebetween water and land, the mattresses form a relatively thin form ofprotection, which has the advantage of requiring minimal excavation toform and is relatively quick to install.

However, the disadvantages of fabric formwork mattresses are significantand have resulted in this method of protection becoming unfavorable overthe last 10 years or so, particularly within the United Kingdom. Adisadvantage with this method of scour protection is that it forms ahydraulically smooth surface (a low mannings n value), which typicallyresults in the scour being deflected elsewhere. Smooth surfaces will notabsorb any of the erosive force of the river and can ever exacerbatedthe scour problem elsewhere.

In addition, this method produces a very unnatural appearance, beingsmooth, dimpled, ‘sand-bag like or mattress-like, the color of which isoff-white/concrete looking, particularly when first placed.

Similarly, extensive mats are relatively inflexible, and the extremitiesare particularly vulnerable to undermining and cracking, reducing theprotection.

Furthermore, this method provides no environmental benefits, and themattresses are very difficult to form protection for anything other thansimple flat surfaces. Non-standard shapes/designs can be custom made butrequire significant time to manufacture. Mattresses are also verydifficult to repair and the benefits gained by using extensivemattresses can be lost if small repairs are needed.

These disadvantages make the use of fabric formwork mattressesunfavorable with consenting organizations around the world and, as aresult, are presently of limited use as a method protecting structuresor river banks against scour.

Consequently, alternative forms of protection are usually preferred,such as rock armor or rip-rap which are coverings of loose rocks, asthey are environmentally more natural and largely preferred by numerousenvironmental consenting groups.

SUMMARY OF THE INVENTION

An aim of the present invention is to provide a scour protection systemwhich overcomes the above disadvantages.

In a first aspect of the invention, there is provided scour protectionapparatus comprising one or more containment means, the containmentmeans placed in a location to prevent scour, each of the containmentmeans substantially filled with matter to form blocks, characterized inthat at least a portion of the outer surface of said containment meansis adapted to have an appearance sympathetic with at least one featureof the location.

In one embodiment, the containment means are bags. Typically, the bagsare made of fabric with a specific base shape and are formed byconnecting seams by sewing, studs, heat-welds and/or the like.Typically, the bags are manufactured from any or any combination ofpolypropylene, polyester, nylon, hemp, elasticated fabrics, and/or thelike.

Thus, fabric with a specific base shape is used to provide the formworkfor the matter to form a block which can be used to provide a system ofinterconnecting blocks. Typically, the base shape and thus each block isone square meter in area or fractions or multiples thereof to allowdiscontinuity of blocks. This form of construction means that the blockscan be used universally and can be manufactured and stockpiled as emptyfabric bags and, thus, always be available ‘off the shelf’. The overallscour protection scheme is easier to design and is more flexible toaccommodate and remove variations in bed profile around any scourfeature than with conventional systems. In addition, individual blockscan be removed and replaced if damaged, for example, without having toremove any other blocks.

Typically, one or more blocks have an increased depth compared to theother blocks so as to be suitable for placement around the edges of thelocation.

In one embodiment, one or more sections of the bags are reinforced,stiffened and/or restrained to ensure the blocks are formed in thecorrect shape and the shape is maintained.

In one embodiment, the bags are formed of foldable sheet material toallow the bags to be moved between a flattened folded configuration andan erect configuration.

Typically, the matter is any or any combination of grout, concrete,sand, stones, and/or other aggregate material.

In one embodiment, the containment means is substantially filled withthe matter after being placed at the location.

Typically, a hose is connected to the containment means to fill the samewith matter and/or release trapped air, water and/or matter.

In one embodiment, the containment means is provided with valve meansand/or filter means to prevent escape of the matter placed therein.

In one embodiment, the containment means is provided with an outer layerand one or more inner layers. In one embodiment, the outer layer ispermeable and one or more of the inner layers is impermeable.

Typically the location is underwater, including any of any combinationof riverbanks, river beds, sea beds, and/or the like.

In one embodiment, the location features are rocks, and the top surfaceof the containment means resembles rock armor. Typically, the topsurface is adapted by physical or mechanical impact and/or by theapplication of heat such that when the containment means has been filledwith the matter, the top surface has a rough, irregular, rock-likeshape. Other surfaces of the containment means can be adapted in asimilar fashion as required.

Alternatively, the appearance can be achieved by tailoring the fabricforming the top surface of the individual blocks to produce a rough andirregular surface, by physical restraints to the expansion of the topsurface, and/or by post expansion deformation of the concrete bags afterplacement. The provision of this deformation and irregular surfacecreates a more natural appearance and also creates a high mannings ‘n’value so that the protection acts more like rock armor scour protectionin absorbing some of the energy of the flow.

Typically, at least a portion of the containment means is colored and/ortextured to resemble features of the location. The texturing and/orcoloring is of particular importance for areas that are easily visible,as discoloration of the blocks occurs naturally over time.

In one embodiment, connection means are provided to connect adjacentcontainment means. Typically, the connection means includes any or anycombination of zips, ties, nuts, bolts, washers, plates, hook and loopfastenings, and/or the like.

In a second aspect of the invention, there is provided scour protectionapparatus comprising one or more containment means, the containmentmeans placed in an underwater location to prevent scour, each of thecontainment means substantially filled with matter to form blocks,characterized in that the containment means is substantially filled withthe matter after being placed at the underwater location.

In a third aspect of the invention, there is provided scour protectionapparatus including at least one containment means formed by a sheetmaterial defining a cavity into which matter is placed to substantiallyfill the same and characterized in that at least one surface of thecontainment means is adapted so as to have a higher mannings ‘n’ valuethan the remainder of the containment means' surfaces.

In a fourth aspect of the invention, there is provided a method ofproviding scour protection to a location, comprising the steps of:

-   -   placing containment means in a location to prevent scour;    -   substantially filling said containment means with matter to form        blocks,        characterized in that at least a portion of the outer surface of        the containment means is adapted to have an appearance        sympathetic with at least one feature of the location.

In one embodiment the adaptation also increases the mannings ‘n’ valueof the portion.

BRIEF DESCRIPTION OF THE DRAWINGS

Specific embodiments of the invention are now described.

FIG. 1 illustrates a schematic view from the side of the containmentmeans of a scour protection system in accordance with one embodiment ofthe invention.

FIG. 2 illustrates a perspective view of the containment means of FIG.1.

FIG. 3 illustrates a side schematic view of the containment means ofFIG. 1 being filled.

FIGS. 4A-4D illustrate a plan view of a scour protection (A) underconstruction with offset blocks in the location; (B) with in-lineblocks; (C) with variable sized blocks; (D) as an example of a completesystem.

FIG. 5 illustrates a side schematic view of an edge toe detail block.

FIG. 6 illustrates a side sectional view of a scour protection system.

FIGS. 7A-7F illustrate a side schematic view of adjacent blocks (A) witha butt join; (B) with an alternative butt join; (C) connected by a zip;(D) connected by an alternative zip; (E) connected with nuts and bolts;(F) connected with nuts and looped-end bolts.

FIG. 8 illustrates a side schematic view of a bag with a folded edge.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1 and 2, there is illustrated containment meansin the form of an individual fabric bag 1 filled with a matter 5 to forma block designed to interconnect with other blocks to cover an area andprovided with a top surface 3 to act like and resemble rock armor. Ofcourse, other surfaces can be configured to resemble rock armor asrequired. The rock armor has an appearance sympathetic to the naturalrock features of the location in this example of a river bed. The shapeof bag 1 defines the bag formwork. In this example, the fabric ismanufactured from high strength synthetic material, such aspolypropylene or polyester, and in this example is permeable to allowthe escape of trapped air or water within the bag.

Heavy duty cotton, hemp, or a similar type of fabric can also be used.However, the ability to heat or physically deform such fabrics islimited, and it is likely that at least top surface 3 would need to betailored by a variety of methods including, but not exclusively,stitching or various physical restraints.

A mixture of fabrics can be used to form the bag. For example, the baseportion of the bag can be made from nylon, and the irregular top surfacecan be formed from an elastic fabric.

Bags 1 have a specific base shape such that the individual blocksinclude a uniformed and regular basal section 2 to allow regular joiningand coverage of numerous blocks to cover an area, in the same way ablocked driveway could be laid for example. The depth of basal section 2can vary, typically between 0.1 m and 1.0 m, depending on the degree ofprotection required and velocity of the flow experienced by theprotection. The seams of the fabric are joined either by sewing withthread for example, a process of heat welding if using synthetic fabric,gluing, stud attachments, zipper, or similar. The fabric can also betailored internally to help retain the desired shape of basal section 2using internal restraints and/or stiffeners made from fabric, metal orplastic to form a suitable framework.

Top surface 3 of each individual block, in accordance with theinvention, is irregularly shaped to resemble rock armor and provide aless artificial appearance. This may be achieved by using a stretchablefabric to form top surface 3. A selection of restraining methods canalso be utilized to allow or restrict expansion of the fabric as it isbeing filled with matter 5 to create an irregular surface. The fabriccan be colored with dye or a surface coating and textured using asand/grit type coating which greatly improves the natural appearance ofthe individual blocks.

The fabric forming the individual blocks incorporates valve means 4 towhich a filling hose 23 can be attached once the block is placed inlocation below the water surface 24, as shown in FIG. 3. Valve means 4incorporates a one-way or cut off valve to prevent escape of concreteonce hose 23 has been removed and the valve is exposed to the water.Valves can be situated on basal section 2 and/or on top surface 3 of theindividual blocks. Bags 1 are filled with matter 5 to form the blocks,as indicated by arrows 25. Matter 5 comprises grout (fine consistency),micro-concrete, regular concrete, specialist underwater concrete, sand,stones, and/or similar material. In particularly environmentallysensitive areas, attachment of hose 23 to bag 1 can be made out of thewater to reduce the possibility of leakage from hose 23 between fillingof a number of bags below water. Additional bleed valves or outlet hosescan be included on any part of the bags to aid filling with mater and/orallow the escape of air and/or water from the bag.

As shown in FIG. 3, the bags can include an impermeable inner layer 6 toprovide better control of matter 5 and reduce the likelihood ofenvironmental pollution from concrete fines, for example, which can leakthrough permeable fabric.

Impermeability may be achieved by application of a fabric coating, suchas rubber, or be an inherent property of the fabric. The fabric may beof high tenacity or be stretchy in nature to achieve the desired effect.The use of hemp or other natural product can also be used and has theadded benefit of being an environmentally more preferable material. Inthis example, the inner layer includes a bleed valve to allow the escapeof any trapped air or water from within, as voids within the concretewould otherwise weaken the concrete protection.

FIGS. 4A-D show an example of how individual blocks 9 are arranged toform the scour protection system. Blocks 9 can be arranged offset inrows and/or columns, as shown in FIG. 4A, similar to the arrangement ofbricks in a wall, or in regular rows or columns, i.e. not offset, asshown in FIG. 4B.

The system is assembled by interconnecting blocks 9. As shown in FIG.4C, the use of varied sized blocks can be used to create a varied, morenatural appearance, for example using standard 1 m blocks 9 with 0.5 mblocks 9′. The system can be configured individually depending on thesize of the scour feature, orientation of the bed and of the structure,or of the desired appearance.

Referring to FIGS. 4A and 4D, a scour protection system is shownprotecting a bridge abutment 7 from the scouring action of water flowingthereby which has resulted in a scour feature 8, in which individualblocks are formed to cover the bed and prevent undermining of theabutment 7. A special edge toe detail block 10, as indicated in moredetail in FIG. 5, is included at the extremities of the system to reducethe possibility of undermining of the extremities of the protection bythe flowing water. This edge toe detail block 10 is typically deeperthan the regular blocks 9 with a significantly extended base 15, suchthat the depth of the block typically exceeds 1 m. An optional rockarmor falling apron 11 can be also included surrounding the blockprotection.

With reference to FIG. 6, there is illustrated a typical arrangement ofthe system in section, showing how the blocks interact and work to formthe protection. The individual formed fabric formwork blocks 9 protectthe bed from further erosion and scour, with the edge toe detail blocks10 forming and protecting the extremities. This system of protectionprotects the abutment 7 from being undermined by the scouring action ofthe flow of water which has resulted in the scour feature 8. FIG. 6 alsoshows a typical pre-scour bed profile 13, and the scoured bed profile 14for comparison.

FIGS. 7A-F show a range of optional connecting arrangement of theindividual bags forming the blocks. The blocks can be unattached to oneanother, shown in FIG. 7A, forming a simple butt join 16 between theindividual blocks, although in reality this butt join will more closelyresemble the simple butt join 16′ shown in FIG. 7B, due to somedeformation of the bags as they are being filled, which will providesome degree of interlocking of the individual blocks.

FIGS. 7C-D show two possible zip attachment arrangements incorporating azip 17 which is formed from nylon but can also less suitably be formedfrom metal.

FIG. 7E shows a possible bolt style attachment 18, including a backingplate 19 with attached bolt onto which is placed a washer 20 and a nut21. Similar configurations using butterfly or looped tie type ends 26 toa bolt fixing are possible and may be more practical as shown in FIG. 7For possible using flexible ties to allow a small movement due tosettlement. The bolt style attachment is fed through pre-formed holeswithin the bags and allows joining of the empty bags. The boltarrangement would then be cast into the block as the bag is filled withconcrete or other matter.

Alternatively, these attachments can be used to attach any style of bagwhere holes through the bags, through which the bolts are inserted couldbe formed on site during construction. A number of bags can thus bejoined above water, placed, and then filled with matter a number at atime.

Referring to FIG. 8 there is shown a block 9 where the bag has a foldededge 22 forming a concertina or bellows effect to the fabric. Byincluding this folded edge 22 within the fabric of the base, a regularand controllable expansion of the bag is allowed as it is being filled.This accommodates some degree of flexibility in the filling of the bagsto better accommodate irregularities in the ground profile beneath theblock and to allow a range of thicknesses of the block that can becreated on site.

It will be appreciated by persons skilled in the art that the presentinvention may also include further additional modifications made to thedevice which does not affect the overall functioning of the device.

1. Scour protection apparatus, said apparatus comprising one or morecontainment means, said containment means placed in a location toprevent scour, each of said containment means substantially filled withmatter to form blocks, wherein at least a portion of all outer surfaceof said containment means is adapted to have an appearance sympatheticwith at least one feature of the location.
 2. The scour protectionapparatus according to claim 1 wherein said containment means are bagswith a specific base shape.
 3. The scour protection apparatus accordingto claim 2 wherein said bags are formed from fabric with connectingseams.
 4. The scour protection apparatus according to claim 2 whereinsaid bags include one or more reinforced sections, stiffeners, and/orflame sections to help form and/or maintain shape of the block.
 5. Thescour protection apparatus according to claim 2 wherein said bags areformed to foldable sheet material to allow the bags to be moved betweena flattened folded configuration and an erect configuration.
 6. Thescour protection apparatus according to claim 2 wherein the specificbase shape is square.
 7. The scour protection apparatus according toclaim 1 wherein said matter is selected from a group consisting ofgrout, concrete, sand, stones and/or other aggregate material.
 8. Thescour protection apparatus according to claim 1 wherein valve meansand/or filter means are provided to prevent escape of the matter placedin said containment means.
 9. The scour protection apparatus accordingto claim 1 wherein a hose can be provided to connect to said containmentmeans, to fill the same with matter and/or release trapped air, waterand/or matter.
 10. The scour protection apparatus according to claim 1wherein said containment means is provided with an outer layer and oneor more inner layers.
 11. The scour protection apparatus according toclaim 10 wherein said outer layer is permeable and one or more of saidinner layers is impermeable.
 12. The scour protection apparatusaccording to claim 1 wherein said apparatus further includes regularblocks and deep blocks, the deep blocks for placement around the edge ofthe location.
 13. The scour protection apparatus according to claim 1wherein said containment means are substantially filled with said matterafter being placed in the location.
 14. The scour protection apparatusaccording to claim 1 wherein said location is under water.
 15. The scourprotection apparatus according to claim 1 wherein said at least onefeature is rock.
 16. The scour protection apparatus according to claim 1wherein said at least a portion of the outer surface is colored and/ortextured to resemble said at least one feature.
 17. The scour protectionapparatus according to claim 1 wherein said containment means is adaptedby physical or mechanical impact and/or by application of heat such thata top surface of said blocks has a rough irregular shape.
 18. The scourprotection apparatus according to claim 1 wherein at least a pair ofsaid containment means is formed from elasticated or deformable fabricthat is adaptable such that a top surface of said blocks has a roughirregular shape.
 19. The scour protection apparatus according to claim 1wherein connection means are provided to connect adjacent containmentmeans.
 20. A scour protection apparatus, said apparatus comprising: oneor more containment means placed in an underwater location to preventscour, each of the containment means substantially filled with matterafter being placed at the underwater location to form blocks.
 21. Scourprotection apparatus, said apparatus comprising: at least onecontainment means formed by a sheet material defining a cavity intowhich matter is placed to substantially fill the same and having atleast one surface if the containment means is adapted so as to have ahigher mannings ‘n’ value than the remainder of the containment means'surfaces.
 22. A method of providing scour protection to a location, saidmethod comprising the steps of: placing containment means in a locationto prevent scour; substantially filling said containment means withmatter to form blocks; and adapting at least a portion of an outersurface of said containment means to have an appearance sympathetic withat least one feature of the location.